Testing equipment for automatic telephone systems



Sept. 9, 1,930. w. A. BRANDT 1,775,550

TESTING EQUIPMENT FOR AUTOMATIC TELEPHONE SYSTEIS Original Filed Sept. 3. 1926 Fzg'l v I2 HI! i 7 1 4 H -P15 9 [9 342 lf "1; i n c; i ii H 'i Z 4 I J y of trafic observationdevices have been de-' Patented Sept. 9, 1930 UNITED STATES PATENT-OFFICE,

WILLIAM A. BRANDT, OF-DREXEL HILL, PENNSYLVANIA, assielvon ro A TO ATIC ELECTRIC me, or onioeeo, ILLI Nois, A cannon-Arron or DELAWARE mnsrme nourrivinix rroa AUTOMATIC 'rnitnrnonnsysrnivrs Application filed September, a, 1926, Serial No. 133,357: Renewed March 5, i930.

Thepresent invention relates to telephone systems. 1

More speclficallypthe invention is concerned with a recording device to be used in automatic telephone exchanges, for recording all calls extended to apredetermined line or station, regardless of whether the station or'the line is busyr or idle. A great number veloped in the past, :and are'well known in the art, all more or less adequately meeting the requirements set up by the complex conditions confronting the modern telephone engineer. The value of traificobservation apparatus is now generally recognized,,since .it is well nighimpossible to cope with the progressing development in telephony Without devices which give an accurate account of the amount of trafiie routed over certain channels or to certain points, in a modern telephone exchange, with its multifarious, and frequently exceedingly complicated equipment. Itmay well be said that telephony has definitely passedithe experimental stage, and that future developments will be, to a considerable extent, based on the results of trailic observation. Devices designed to record traffic have, therefore, become an indispensable tool in telephony.

One or the requirements of trafiic observation is to record the total amountof trafiic routed to a certain line o-r station. In other words, it is highly desirable to know how many calls are extended to a certain line or station within a predetermined time.

It is the chief object of the present invention to meet the requirements outlined above.

In accordance with this object,the invention designed to-record, on a pen-recorder, all calls'extended to a predetermined sub- .scrihers line, or other line, regardless whether the line is available or engagedina connection previously completed.

However, it is not sufiicient to record merely the number of calls extended to a certain line, or station, but it is of equal importance to record the length of time a line or a station is engaged, and the number of times the line, or station, is called while busy.

The necessity of this will bereadily apprehended if it is considered, that, aslong as a conversation is carried on, a number. ofappareitus-(trunk lines and switches )are withdrawn from trafiic. Since the switches and the trunk lines overwhich a call is ex- ;tended are common to a large part oftheremaining exchange equipment, itlwill be obvious thatthe holding time, that is, the period for which thevarious apparatus are engaged, is Just as important as the frequency with which they-are takeninto use, 1

Accordingly, itis also an objectof the invention, to record the length of time of each successful xcall terminating at a certain line or station, and the length oftime of each subsequent call extended to that line or sta tion' whilebusy. To explain this .a littlemore in detail, when a line .or station issca lled while busy,the calling party receives a busy signal. However, as each person has his in} dlvldualpersistency, the time until a calling party restores the receiver to the switchhook,

serve and to record the amount of traffic routed to them. The preservationi of flexif bility being an essential object of the inven tion,,the samewas designed with the view of furnishing a portabledevice for observing subscribers stations, as well as trunk lines,

in fact, any line accessible'from an automatic switch. The phrasing line or station, or equivalent terminology employed in this specification has to be understood in this sense. .Accordingly, the recording equipment disclosed, may be employed for obsorving certain subscribers station, by connecting it up'with. all the connectors which have access'to that station, orlif slightly modified, it may beused for observing a certain trunk line accessible it to automatic switches, by connecting it up with these switches.

Theutility ofthe invention be apparpractice.

ent from the detailed explanation which is yet to follow, and which should be read in connection with the single sheet of drawings, which forms a part of the specification. However, before entering a detailed discussion, it will be advisable to give a brief account of the figures shown in the drawing.

Stated generally, 1 shows a recorder as intimated in the above paragraph, and Fig. 2 shows schematically how such recorder is connected up in practice. Details of the figures shown, and symbols used in the figures will now be explained more particularly.

In Fig. 1, is shown the recording device, comprising the relays 1-5, inclusive; a small rotary switch M with its motor magnet 6, release magnet 7, and wiper 8; 9 is the offnormal contact operated by the switch M; 10

and 11 are two conductors by means of which the observation of a certain line or subscribers station is adjusted; 12 and 13 are conductors to be connected up with a common pen-recorder; 14 is a plug for connecting the device to a connector or to another switch which has access to the line under observation; 22 is a common signal device which is actuated in case of a faulty operation.

Fig. 2, illustrates schematically how the recording device, shown in Fig. 1, is used in It is assumed in this figure that a certain line is to be observed, and that this line is accessible to ten switches, 2635.' A device, such as the one shown in Fig. 1,will be connected up by means of a plug with each of these switches, the connections being indicated by leads 3645 inclusive, and the recording devices being shown at 46-55 inclusive. All these recording devices are connected up with a common pen recorder 56 which is equipped with as many pens as there are recording devices. It being as sumed that there are ten recording devices, the common pen recorder will be equipped with ten pens designated 57 to 66 inclusive (only the first two and the last pen being shown in the drawing). All pens record on the common paper tape 67.

Throughout the drawing Fig. 1, there are shown a plurality of ground and battery connections. It will be understood, however, that thi hasbeen done only for convenience of description and that there is only one battery in practice, preferably the exchange battery, which may be connected to the recording apparatus in any well known and approved manner.

The automatic switch, having access to a certain line which is to be observed, has not been shown, in order to keep the drawing as simple as possible, Those switches are well known to every one familiar with telephony. Each of these switches is equipped with a test jack, which is utilized in the present case for connecting up the recording apparatus.

Having given a general account of the invention, and a detailed account of the drawings and symbols used, a detailed description of the disclosure will now be proceeded with. It shall be assumed, for this purpose, that all calls extended to a certain subscribers telephone line shall be recorded and that this line is see le to a number of connectors as indicate :1 2. Accordingly, the portable recording apparatus is moved to the board containing these connectors, and the devicesare connected up by means of plugs, such as 14.

Each of the subscribers lines accessible to these connectors can be reached by operating any one of the connectors in accordance with the last two digits of the directory number. It shall be assumed, that it is desired to record the calls extended to a subscribers line whose telephone'number ends with two digits of the same numerical value, for example 4-4:.

The lead 10 is connected, in this case, to contact 4 of the switch M; the lead 11 is left open,and lead 18 is connected to a corresponding pen in the common pen recorder. This adjustment is made in all of the recording devices, 4655, inclusive, shown in Fig. 2'.

When a connector is seized, its release conductor is grounded in the usual manner. Since a recording apparatus, such as the one shown in Fig. 1, is connected up with each connector, by means of plug 14 which is inserted into the test jack of the connector, this ground will cause the operation of relay The relay operates its armature 17, thereby opening a point in the release circuit of the switch M.

Relay 1, whichis a polarized relay, is connected in series with a condenser, in bridge ol? the talking conductors of the connector switch. Accordingly, this relay operates in response to the impulses delivered to the connector. In response to the first digit, relay 1 will intermittently operate its armature 15, thereby producing current impulses for op erating the magnet 6 or". the switch M, from battery in series with relay 2. The latter, being a slow acting relay, remains energized during impulsing. It opens its armature 16, removing ground from the wiper 8, and closes its armature 21, connecting ground to a common slow acting signal device 22. If the rotary(and as will be seen later, also the release)operation is faulty, this signal device will be operated at the termination of a certain period of time. The wiper 8 of switch M advances as indicated by the arrow.

If the digit delivered to the connector is anything but four, nothing happens on the recording device, except that the wiper 8 rein ains on the contact to which it was advanced. When the connector releases, the wiper rcturns to normal position, due to the circuit for the release magnet 7 being closed at the release of relay 3, from ground, oil normal 1;, tion of relays and 4, from springs 9, back contactand armature 17, re

lease magnet 7, slow acting relay 2to battery.

. a it However, it the first digit is four, which is thefirst digit of the numberto be observed, the wiper 8 is advancedto contact l. The relay 2 releases duringthe interval between the digits, and closes a circuit for theoperaground, back contact and armature 16, wiper 8, contact 4:, lead 10, armature 19 and itsba ck contact, relay 5, upper winding of relay 4 to battery; Re-

lay a locks itself over its lower winding and ar1nature 23 to ground on the release trunk, and connects the leadlO through, to the pen recorder, over its armature 19, thereby disconnecting relay 5. I The latter relay, while operated, closes a circuit for releasin the an switch M, from ground, front'contact and armature 20, release magnet .7 and relay 2 to battery.

When the nextdigit is delivered to the connector the switch M is again advanced as previously explainejd. Now, if this digit is anyi thing but foulgfnothing will happen unti the apparatus is released when the connector isfreed. However, if this digit is also four,

the wiper8. will again step to the fourth contact. Relay 2 restorcsshort'ly afterthe termination of the impulses and closes a circuit over its armature 16, wlpcr 8, contact 4, lead to the corresponding pen. This last circuit will persist throughout the duration of the connection; The pen recorder will record the call. i v I If the subscribers telephone number ends in two digits ofa difierent numerical value,

as -suchas 31 or 8 4, etc.,the lead 10 is connected to the contact corresponding tothe first ch in-while the lead 11 is connected to the contactcorresponding to the second digit. Inthis case, the lead 12 "is connected to the ran the cnuuncn pen recorder. The operationis then substantially thesame as already explained, i. e., the switch wiper 8 is advanced, in responseto the first digit delivered to the connectoryto the corresponding contact in the bank of switch M, Relay 2 deenergizes after the termination of the first digit and connects ground by means of its armature 16 to the switch wiper 8, thereby effecting the operation of relays 5 and 4. Relay 4 looks itself over its lower winding and armature 23 to the release trunk, disconnecting relay 5. During the time relay 5 is in operated position, with its armature closed, the release circuit for the switch M is completed as be- U5 fore. In response to the second digit, the

trunk underobservation wiil effect switch Wiper Sis advancedto the correspond i gcontact, *to wh1ch 1s now connected the,

lead 11 Relay 2 releases at thetermination of the impulses, completing the circuit for b the pen recorder from grounchbackcontact and armature 16, wiper8, lead 11, armature 18 and its front contact, and lead12.

iielay 2 1s common to both, the rotaryand release circuit, and removes ground from the -'wiper when either isoperated, in accordance with the usual practice to remove potential from a wiper while it brushes over the bank contacts.

As each connectoris temporarily associated with a recording device, it will be readily-ago,

the line or the operation oil-therecordingapparatus in the manner described.

seen, that all calls extended to "All calls willtherefore be recorded on the pen recorder. of the tape will show seriesof dashes. The number of these dashes will correspond tothe' niunber of connectionsto the line or trunk under observation. It will be seen that the length of time a connector sfoccupied onthisetgo number will deternnne the length of a dash onthetape. If, w iile theline is'busy, a connector establishes connection with this line, the calling subscriber receives a busy tone. V fhile the subscriber is listening to the busycer) signal the pen recorder will record thetime. Busy calls will therefore show dots or small dashes on the tape, as usually the calling party hangs up soon after the'busy signal 1 is received. Therefore, the tape will fu1.'r1isht"j an excellent record, both of the holdingtime and number of tnnes'a line was called when 10, armature 19 and its front contact, lead '13,

busy. In other 'words, successful as well as unsuccessful calls will be recorded both asto the holding time of the switches and as to the frequency of occurrence. I

It will be seen from the above description that the j present invention is simple 1n. lts application and represents an. excellent means 7 for recording calls extended to a line ortrunlm 1 w VVhile there 18 shown only one way of carrying out the inventiommany other applications will readily suggest themselves. It is thereforerequested that the interpretation of the invention is not limited by the p'reciseang structure disclosed, but only by the claims 1 which follow.

What is claimed is: b 1. In a telephonesystem, lines, means for extending connections from calling lines tow go a called line, and means forrecording any call and the duration ofany call extendedto recording the duration of calls extended to said called line while said line is busy."

An inspection 3. In a telephone system, lines, means for extending connections from calling lines to a certain called line, means for recording the duration of each successful connection, and means for recording the waiting times of callmg lines attempting to establish connection with said certain called line while said line is busy.

4. In a telephone system, lines, means for extending connections from calling lines to a certain called line, a recorder including a moving tape, means for recording on said tape the duration of each connection, and means for recording on said tape all calls extended to said certain called line while said line is busy. I

5. In a telephone system, lines, means for extending connections from calling lines to a certain called line, a plurality of recorder units adapted to operate a common pen recor'der having a moving tape, means for recording on said tape the duration of each successful connection, and means for recording on said tape the waiting times of calling lines desiring to establish connection with said certain called line while said line is engaged in a connection previously completed.

6. In a telephone system, a plurality of antomatic switches, a called line accessible to said switches, a portable recording device, means for temporarily associating said device with said switches and means associated with said device for recording any call extended to said called line, regardless of whether said line is busy or idle.

7. In a telephone system, calling lines, a called line, a plurality of automatic switches accessible to said calling lines for extending calls to said called line, a portable recording device, means for temporarily associating said device with said switches, means in said device for operating the same under control of a calling line, and means associated with said device for recording the duration of each call extended to said called line, regardless of whether said line is busy or idle.

8. In a telephone system, calling lines, a plurality of automatic switches, a called line accessible to said switches, a portable record ing device, means for temporarily associating a recording device with each one of said switches, a plurality of relays associated with each device, means for operating said relays under control of a calling line, and means in said device responsive to said relay for re cording any call extended to said called line, regardless of whether said line is busy or idle.

9. In a telephone system, a plurality of automatic switches, called lines accessible to said switches, a portable recording device, means for temporarily associating said device with said switches, and means in said device for recording the total number of calls and the duration of each call extended to a certain line, regardless of Whether said line is 10. In a telephone system, a pluralit of automatic switches, called lines accessib e to said switches,a portable recording device, means for temporarily associating said device with said switches, and means associated with said device for recording the total amount of time consumed by each of said switches in holding established extensions to a predetermined called line, regardless of whether said line is busy or idle.

11. In a telephone system, a plurality of automatic switches, called lines accessible to said switches, a portable recording device, means for temporarily associating said device with said switches, a pen recorder associated with said device, and means in said device controlled by a calling line for actuating said pen recorder to record the total amount of time consumed by each of said switches in holding established extensions to predetermined called line, regardless of whether said line is busy or idle.

, busy or idle.

12. In a telephone system, a plurality of automatic switches, called lines accessible to s id switches, a port-able recording device having a plum lity o'i'control units, means for temporarily associating said units with said switches, a pen recorder associated with said device having a plurality of pens in number corresponding to said units, and means in each of said units controlled by a calling line for actuating one of said pens in said pen recorder to record the total amount of time consumed by each of said switches in holding established extensions to a predetermined called line, regardless of whether said line is busy or idle.

13. In telephone system, pluralityof automatic switches, called lines accessible to said switches, a portable control device having a plurality of control units, means for temporar ly associating said units with said switches, a recording apparatus associated with said device, means in said units controlled by a calling party to actuate said apparatus for recording the total amount of time consumed by each of said switches in holding established extensions to a called line, regardless of whether said line is busy or idle, and means in said control units for predetermining the line for recording the traflic thereover.

i l. In a telephone system, lines, substation controlled switches having access to said lines, a polarized relay, a recording device arranged to oo-opcrate with said relay, means for temporarily associating said relay with any one of said switches, and means actuated by said relay for operating said device to record Xtensions to predetermined lines regardless or" whether said lines are busy or idle.

15; In an automatic telephone system, a

the total time said switches consume in calls to a predetermined line, regardless of the busy or idle conditions thereof.

16. Inna telephone system, a plurality of automatic switches operated by impulses transmitted thereto over calling lines, a certain called line accessible to each of said i switches and connected thereto when'any one of said switches is operated by a predetermined number of impulses, a recording device, and means associated with each of said switches for counting the impulses transmitted thereto, said means operating said recording device when the number of impulses transmitted is said predetermined i to number, to make records of the connections to said called line.

17. In a telephone system, an automatic, switch operated by impulses transmitted thereto over a calling line, a certain called line accessible to said switch and connected to when said switch is operated by apredetermined number of impulses, a counting switch associated with said automatic switch and operated in synchronism therewith to count the impulses received thereby, a recording device, and means operated by said counting switch when saidautomatic switch receives said predetermined number of impulses for operating said recording device to record the connection to said called line by said automatic switch.

18. In a telephone system, a two-motion switch directively operated by series of impulses over a calling line, a certain called line accessible to said switch and connected thereto when said switch is operated by two predetermined impulse series, a recording'device, a rotary switch having a normal position and operated in synchronism with said two-motion switch for counting the impulses of all series received by said two-motion switch, and means operated by said rotary switch when the first of said two predetermined impulse series has been received for preparing said recorder for operation and for returning said rotary switch to its normal position, said rotary switch responsive to the reception of thesecond of said predetermined impulse series for operating said recording device to record the connection to said called line by said two-motion switch.

19. In a telephone system, a pair of automatic switches operated simultaneously by impulses transmitted thereto line, a called line accessible swltches and connected thereto when said over a calling switches are operated by a predetermined number of impulses, and means operated by the other of said switches when said switches are operated by said predetermined number of impulses, for recording the connection of said one switch to said called line.

20. In a telephonesystem, a'pair of auto",

matic switches directively operatedjsimultaneously by the same two series of impulses transmitted thereto over a calling line, one of said switches having a normal position, a called line accessible to the other of said switches and connected thereto when said switches are operated by two predetermined impulse series, automatically operating means for returning normal position after the transmission of the first series of impulses, and means prepared for operation and then operated by said one switch whenit is operated by said two predetermined-impulse series, for recording the said one switch to its connection of said other switch to said called line. c t

In witness whereof, I hereunto subscribe my name this 28th day of August, A. 111926.

WILLIAM A. BRANDT.

to one of said I 

